It has been thought that oligosaccharides in glycoproteins have the functions, for example, of retaining the stereo structure of the protein and acquiring resistance for preventing the protein from decomposing with proteases. It has recently been revealed that oligosaccharides in glycoproteins participate in the phenomena of life such as fertilization and differentiation, signal transmission, canceration, intracellular transport of proteins and control of physiological activity. The clarification of the relationship between the bonding molecules on the surface of cells, glycoproteinaceous hormones and like oligosaccharides and the functions thereof has matured to the concept of glycoscience consortium. While the functional research on oligosaccharides has presently been conducted chiefly on sugar transferases (oligosaccharide genes) for effecting biosynthesis of oligosaccharides, sugar transferases are also preserved by genome information and participate in the functions of life through cooperation with other proteins. From this viewpoint, it is necessary to conduct functional analysis of oligosaccharides through structural glycomics procedures for capturing and analyzing the overall picture of oligosaccharides developing in the cells and tissues.
The structural glycomics in glycoscience functions to comprehensively analyze the oligosaccharide recognition mechanism which plays an important role in many phenomena of life, and this function is an indispensable element in functional glycomics. The technical factors required of structural glycomics are high comprehensiveness, high throughput, high sensitivity and high precision.
The structure of oligosaccharides in glycoprotein is presently analyzed by labeling oligosaccharides cut out from a protein with a fluorescent material and thereafter analyzing the oligosaccharides by high performance liquid chromatography (HPLC) and mass spectrometry (MS). This process has become useful means owing to a dramatic advance in mass spectrometry (Nonpatent Literature 1 to 4), and anion exchange column chromatography has been exclusively used for separating sialo oligosaccharides (Nonpatent Literature 5).    [Nonpatent Literature 1] Biomed Chromatogr. 16:103-115 (2002)    [Nonpatent Literature 2] Anal Biochem. 206: 278-287 (1992)    [Nonpatent Literature 3] Biochem Soc Trans. 21:121-125 (1993)    [Nonpatent Literature 4] Chem. Rev. 102: 321-369 (2002)    [Nonpatent Literature 5] Biochim Biophys Acta. 705: 167-173 (1982)
However, the comprehensive analysis of oligosaccharides in cells and tissues involves the problem of the versatility in the modification of the nonreducing terminal of sialic acid, fucose or the like and the branching of the oligosaccharide, so that it is impossible to fully separate the oligosaccharides which are present conjointly and to obtain a satisfactory result. Especially, the ion exchange column, which has no specific separating function, not only fails to effect full separation but also requires desalting treatment subsequent to the separation procedure, and is therefore not practically useful.
Accordingly, it has been earnestly desired to provide a useful method which is capable of fully analyzing the structure of oligosaccharides which is specific to particular cells or tissues, with consideration given to the nonuniformity in the information as to such oligosaccharides.
An object of the present invention is to provide means for individually separating and obtaining oligosaccharides from a mixture thereof like those present in cells or tissues.
Another object of the invention is to provide means for analyzing the structure of each oligosaccharide compound separated off.
Still another object of the invention is to provide novel oligosaccharide derivatives.